1. Field of the Invention
This invention pertains to testing system for and a device for testing electrical modules.
2. Discussion of the Background of the Invention and Material Information
A substantial contribution for the assurance of quality and reliability of complex technical systems is accomplished via suitable testing processes during the production phases thereof. For the testing of electrical circuit boards or modules the processes are used either singly or preferably reciprocally that are described in Qualitat und Zuverlassigkeit technischer Systeme by A. Birolini, Springer Verlag, Berlin 1991, Third Edition, pages 268-280. During a pre-control phase the built-up modules are visually inspected and are electrically tested with reference to their basic properties. In addition, thermic cycling (for example from -20.degree. C. to +80.degree. C. with gradients of 10.degree. C./min.), vibratory cycling as well as long initial break-in at a normal operating temperature, are initially provided. In order to detect hidden deficiencies and reliability problems in environmental and reliability testing, extreme temperatures, additional thermal cycling, vibrations, humidity and ESD testing are also initially provided. During the previously noted tests the supply voltage should preferably also be switchable. Electrical testing is also of basic importance which is accomplished via known devices either before or after the previously-described tests. For such testing, a system analyzer is initially provided which determines the correspondence of the working of the tested module with a predetermined nominal value or behavior.
In known testing devices, up to this time, cold, heat and humidity chambers were provided. Vibration testing was accomplished in a further device. The electrical testing of the utilized modules was thus rather costly. Such electrical testing was practically not possible during the treatment process. For the thermal testing, for example, long, tunnel-shaped ovens were utilized through which individual modules were transported via a conveyor belt. Naturally, within these tunnel-type ovens the modules were not accessible for electrical testing.
In addition, the space requirement for these chambers, tunnel ovens and conveyor belts was considerable, which, in addition to the high cost for the test devices also caused considerable expense for the required premises. Furthermore, the time requirement for the entire quality testing was very high, since the modules had to be moved and exchanged, each time, within the tunnel oven and between the chambers and the devices.